Twist-drill-grinding apparatus.



1%. 821,849. I PATENTED MAY 29, 1906.

' G. BENIGKE.

TWIST DRILL GRINDING APPARATUS. APPLICATION FILED APR.6,1905.

2 SHEETS-SHEET 1 No. 821,849. PATENTED MAY 29, 1906.

G. BENIGKE.

TWIST DRILL GRINDING APPARATUS.

APPLICATION FILED APR.6,1905.

2 SHEETS-SHEET 2.

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EPAENT @FFTQE.

GEORG 'BENICKE, or- ()FFENBACH-ON-THE-MAIN, GERMANY, assleNon OF' oN -HnLF. ro THE FIRM or ERSTE oFFENBAoHER SPECIAL- FABRIK FUR SCHMIRGELWAARENFABRIKATION MAYER & SCHMIDT, or OFFENBAUH-ON-THE-MAIN, GERMANY.

TWIST-DRILL-GRINDING APPARATUS.

Specification of Letters Patent.

Patented May 29, 1906.

Application filed April 6, 1905- Serial No. 254,121.

To all whom it may concern:

Be it known that I, GEORG B'ENICKE, a sub ect of the German Emperor, and a resident of Ofienbach-on-the-Mai-n, Germany, 5 have nvented anew and useful. Twist-Drill- Grmdmg Apparatus, of which the following is a specification.

By means of the apparatus illustrated in the accompanying drawings twist-drills may 1 p be automatically ground in a manner similar to that effected by hand with the aid of the 1(:rdmary known twist-drill-grinding appara- Advantages to/be derived in the use of my 0 apparatus are that the angle to which the point or lips of the drill are ground, as well as theam'ount ofthe backing, may be regulated while the grinding is being effected. I ,m aware that there are apparatus which are ained, but in their construction, as Well as in hein operation, they difier essentially from e. In the accompanying drawings, Figure 1 is side. elevation of my apparatus. Fig, 2 is a plan view showing a drill adjusted ready for the commencement of theigrinding operation, one of its cutting edges or lips being shown a plied to the. grinding-wheel. Fig. 3 is a 39- p anview showing thedri l at the end of its circular movement; Fig. is a cross-section 1; Online a b of Fig.1. Fig. 5 is a longitudinal section on line 0 d of Fig. 2, and Fig. 6 is a lon- -.gitudinal section of the drill-holder on line 6 ofgiig. 2. g

' he construction and operation of the apparatus are as follows: By means of a ulley 1 rotary motion is imparted to a she-l t 2 and consequently also to toothed cone-wheels 3 and 4, which are slidable thereon, Figs. 1 and. 5. Both the wheels 3 and 4 are provided with slidable sleeves, which are rotatably carried in bearings 5 6, which latter are fixed or screwed to two superposed supporting-plates 7 8, the bearing 5 to the lower plate 7 and the bearing 6 to, the upper plate 8; The supporting-plate I 7 is provided with' a screwed spindle '34,"

whereby it may be moved in a horizontal direction, Fig. 4, and the plate 8, which 1s not 7 provided with such a screwedspindle, 1s als.o

adapted .to be moved in ahorizontal direcintended to enable .these advantages to be attion' and is provided with springs 23 24, which tend to draw. said plate rearwardly. The plate 8 is provided with a spindle 10, on which, and supported by the plate 8, an arm 9, carrying the drill supporter holder, is pivotally mounted.

The spindle 10 has its bearing in the plate 8, and also in the late or equivalent whereby the bearing 6 is 'ed to said plate 8, and on said spindle 10 two wheels are mounted, on the lower end a conical toothed wheel 11, and on the upper part a toothed wheel 12, Fig. 5. The wheel 12 is situated within a recess formed in the boss of the arm 9 and serves to transmit therotary motion of the latter to wheels 13 and 14, also carried in recesses, Fig. 6. The wheel 14 is keyed on a spindle 15, carried by an enlargement on the arm 9, and said spindle also carries at its upperend a cone-pinion. 16. This pinion 16 drives a toothed wheel 17, which is fixed on the drillholder 18 and serves to rotate the latter. In the center of the drill-holder 18 the drill 36 is fixed in any suitable known manner, the ar-- rangement being such that said drill will be rotated with the holder, whether either the plate 7 or 8 is moved or whether the arm 9 is rotated about the spindle 10.

The cone-pinion 3 gears with and rotates a cone-wheel 19, which is mounted on a spindle 20, Fig. 5. The spindle 20 is rotatably carried by the plate 7, and its upper end is provided with a disk or'the like having-a pin 21 eccentrically mounted thereon. This pin engages in a slot in a plate 22, so that by the rotation of the spindle 20 said plate will be reciprocated backward and forward. The plate 22 is slidable on the plate 8, Fig. 5, and the plate 8 will be drawn or pulled rearwardly by the sprin s 23 24 until a roller 25 comes in contact wit plate 26 is rotatably mounted on a bolt 27, which is fixed onthe supporting-plate 7. Further, the plate 26 rests against a regulator-screw 28, by means of which said plate may be adjusted. The screw 28 is carried by a horn'29, also fixed on the plate 7, Fig. 5. At one side on the plate 22, Fig. 2, there is a lu or equivalent 30, through which a secon regulating-screw 31 passes. Against this screw 31 the enlarged part of the arm 9 is drawn by means oi a spiral spring32, said a. segmental plate 26. This arm, as already stated, being rotatable on the spindle 10. By means of the screw 31 the angle of the arm 9 relatively to the face of the U tive proportion of the wheels which rotate this spindle being such that when the drill makes one revolution the spindle and its pin 21 have made two revolutions. In Fi 2 the drill, as already stated, is shown adusted for the commencement of the grinding 0 eratio'n. By the rotation of the in 21 the p ate 22 is moved so that the regu atorscrew 31 partly rotates the arm 9 around its spmdle 10. By reason of the movement of the plate 22 the springs 23 24 are enabled to draw the plate 8, together with the drillholder, to some extent in a rearward direction, so that the roller 25 is always in contact with the sloping or angular ed e of the plate 26, whereby the angle of the rill relatively to the grinding-disk is so changed as to cause the necessary backing to be eflected. When the eccentrically placed pin 21 has made half a revolution, the axis of the drill will have been moved from the position 6 f (shown in Fig. 2) to that indicated by the line 9 h, the drill itself-having rotated to the position shown in Fig. 3. It will thus be seen that the surface ground on the half of the drill is of spiral form, the cutting edgebeingv ground to an angle which the line 6 f makes with the face 0 the grinding-disk, and this an .le, as the drill slowly rotates, is graduall a tered until at the end of the grinding stro e the axis of the drill will make an angle,

(indicated by the line 9 h,) as shownin Fig. 3, with the face of said disk. The various angles, or rather this constant, change'in the angle from 6 f to g h, is essential to insure a proper cutting action of the drill. The ength of the s 01: in the-plate 22 is such that when the position shown in Fig. 3 is reached the pin 21 will revent the springs 23 24 moving said plate rther. The pin 21 by moving the plate 22 also moves the plate 8,-to gether with the drill-holder and drill, away rom the grinding-disk and also the roller 25 from the plate 26. This continues until the.

drill has made a further quarter of a revolution, and the pin 21 consequently a half-revolution. After this the grlnding of the other I half of the drill, or the other cutting ed e,1

will be effected in the manner already escribed.

It will be seen that the screws "28 and 31 i are of considerable importance to the roper The former 0 these side of the plate 26 to be changed, determines the amount of the backing, and the Further, by reason of the cutting end ofthe i drill being pressed against the grinding-disk by the spring 32 the said end ma by merely pushing against the free end of t e arm 9, be

-moved away from the grinding-disk to permit its being ins ected.

Having now iiilly described my said invention and in what manner the same is to be performed, what I claim, and desire to secure by Letters Patent, is

1. In a device of the class described a grinding-wheel, means for rotating the grinding-wheel, a drill-holder, means for securing the drill in the holder, means for yieldingly forcing thedrill-holder toward the grindingwheel so as to keep the drill in contact therewith, means for rotating the drill-holder and means for vibrating the drill-holder on an axis at an angle to the axis of the grindingwheel. 1

2. In a device of the class described a grinding-wheel means for rotatin the grinding-wheel, a drill-holder, means or securing the drill in'the holder, means for yieldingly forcing the drill-holder toward the grindingwheel so as to keep the drill in contact therewith, means for automatically rotating the drill-holder, and means for automatically vibrating the drill-holder on an axis at an angle Y to the axis of the grinding-wheel.

'3. In a device of the class described, a grinding-wheel, means for rotatin the grind- IOO lng-wheel, a drill-holder means or securing the drill in the holder, means for yieldingly forcing the drill-holder toward the grindingwheel so as to keep the drill'in contact there-.

with and means for automatically shifting the axis of the drill during the grinding.

4. In a device of the class described, a

ing-wheel, a drill-holder means or securing the drill in the holder, means for yielding ly forcing the drill-holder toward the grindingwheel so as to keep the drill in contact therep I.

with, means for rotating the drill holder, means for vibrating the drill-holder. on an axis at an angle to the axis of the grinding wheel, and means for-regulating the distance traversed by the drill-point.

6. In a device of the class described a grinding-wheel, means for rotating the grinding-vvheel, a drill-holder, means for securing the drill in the holder, means for yieldingly forcing the drill-holder toward the grinding- Wheel so as to keep the drill in contact therewith, means for automatically rotating the drill-holder, means for automatically vibrating the drill-holder on an axis at an angle to the axis of the grinding-Wheel, and means for regulating the distance traversed by the drill-point.

7. In a device of the class described, a grinding-Wheel, means for rotating the grinding-Wheel, a drill-holder means for securing the drill in'the holder, means for yieldingly forcing the drill-holder toward the grindingwheel so as to keep the drill in contact there with, means for automatically shifting the axis of the drill during the grinding, and means for regulating the distance traversed by the drill-point.

8. In a device of the class described, a grinding-wheel, means for rotating the grinding-Wheel, a drill-holder means for securing the drill in the holder, means for yieldingly forcing the drill-holder toward the grindingle s wheel so as to keep the drill in contact therewith, means for automatically shifting the angle of inclination of the drill and for rotatport, a sliding plate, means for normally forcing the sliding plate toward the grindingwheel, a vibrating lever carried by the sliding 3 5 I late, a drill-holder carried by the vibrating ever, and means for vibrating the lever and rotating the drill-holder during the grinding operation.

In testimony WhereofI have hereunto set 40 my hand in presence of two Witnesses.

GEORG BENICKE.

Witnesses KARL BROCKMANN, JEAN GRUND.

the distance traversed by the 0 

